Flake aligner including baffles supported on continuously moving conveyor

ABSTRACT

Apparatus for forming a continuous elongated loosely felted mat of thin elongated wood flakes with the flakes being aligned in mutually parallel interleaved relation. The apparatus includes a plurality of belts positioned in adjacent side-by-side relation and for continuous movement so as to define a supporting surface for the mat. A plurality of sets of thin planar baffle plates are provided, each set including a plurality of thin planar baffle plates supported in coplanar alignment and in edge-to-edge adjacent relation. The baffle plates are positioned between a hopper for depositing wood flakes and the supporting surface and function to align the wood flakes in substantially mutually parallel relation in substantially parallel relation to the direction of movement of the supporting surface and to maintain the wood flakes in substantially parallel alignment as the flakes fall from the hopper onto the supporting surface. Each of the sets of baffle plates are positioned between pairs of belts and are supported for movement with the belts, and the baffle plates of one set are parallel to and spaced closely adjacent to baffle plates of an adjacent set.

FIELD OF THE INVENTION

The invention relates to compressed wood particle products and moreparticularly to apparatus for forming a continuous loosely felted mat ofelongated aligned wood flakes, the mat being adapted to be compressed toform a composite wood product.

BACKGROUND PRIOR ART

As set forth in the U.S. Lund et al. Pat. No. 4,241,133, issued Dec. 23,1980 and assigned to the assignee of the present invention, it has beenfound to be desirable in the construction of compressed or compositewood particle products to employ wood flakes which are very thin andwhich have a length at least several times their width and to align thewood flakes in mutually parallel alignment and in alignment with thelongitudinal axis of the product being produced. This produces a producthaving substantially improved strength characteristics in the directionof alignment of the wood flakes. The production of such compressed woodproducts formed from an assembly of wood particles first requires theformation of a loosely felted mat of wood particles. The mat is thencompressed to form a densified panel or board. One problem encounteredin forming the loosely felted mat is that the alignment or orientationof the elongated wood flakes is made difficult because the wood flakes,which are very light and comparatively fragile, have to be handled enmasse, and this has resulted in the clogging of the known machines thatwere tried for this purpose.

Examples of prior art attempts to design suitable apparatus for formingmats of aligned wood strands are set forth in the U.S. Elmendorf Pat.No. 3,478,861, issued Nov. 18, 1969; the U.S. Elmendorf Pat. No.3,220,743, issued Aug. 24, 1965; the U.S. Turner et al. Pat. No.3,721,329, issued Mar. 30, 1973; the U.S. Urmanov Pat. No. 3,963,400,issued June 15, 1976; and Canadian Pat. No. 597,941, issued May 10,1960.

Attention is also directed to the U.S. Hostettler Pat. No. 3,226,764,issued June 4, 1966; the U.S. Hostettler Pat. No. 3,070,838 issued Jan.1, 1963; the U.S. Carlsson et al. Pat. No. 3,692,612, issued Sept. 19,1972; the U.S. Paerels et al. Pat. No. 3,372,217, issued Mar. 5, 1968;the U.S. Axer et al. Pat. No. 3,824,058, issued July 16, 1974; and theU.S. Chapman Pat. No. 2,992,152, issued July 11, 1961.

Attention is further directed to the U.S. Shockley et al. Pat. No.3,048,888, and the U.S. Zilver Pat. No. 2,968,386, issued Jan. 17, 1961.

SUMMARY OF THE INVENTION

The invention includes apparatus for forming an elongated continuous matof elongated wood flakes mixed with a binder and adapted to becompressed to form a densified composite wood product. The apparatus ofthe invention includes means for depositing elongated wood flakes on asupporting surface and for aligning the wood flakes in mutually parallelrelation. The means for continuously feeding and aligning includes ahopper containing wood flakes and for depositing the wood flakes in anevenly distributed relation on a supporting surface, and the supportingsurface is comprised of a plurality of parallel adjacent belts supportedfor continuous movement and defining a grate. Means are also providedfor causing alignment of the wood flakes as they are deposited on thesupporting surface and for maintaining alignment of the flakes as theydrop from the hopper onto the supporting surface.

More particularly, the invention includes apparatus for forming acontinuous elongated loosely felted mat of thin elongated wood flakeswith the flakes being aligned in mutually parallel interleaved relation.The apparatus includes means defining a mat supporting surface andincluding a plurality of belts positioned in adjacent side-by-siderelation and means for supporting the belts for continuous movement as aconveyor. Means are also provided for depositing wood flakes onto thesupporting surface to form a loosely felted mat. The apparatus alsoincludes means positioned between the means for depositing and thesupporting surface for aligning the wood flakes in substantiallymutually parallel relation and in substantially parallel relation to thedirection of movement of the supporting surface and for maintaining thewood flakes in substantially parallel alignment as the flakes fall fromthe means for depositing onto the supporting surface. The means foraligning and maintaining alignment includes a plurality of sets of thinplanar baffle plates, each set including a plurality of baffle platessupported in generally coplanar alignment and in mutually adjacentrelation so as to form an elongated continuous baffle and each set beingpositioned between pairs of the belts. The baffle plates of one set aresupported parallel to and spaced closely to baffle plates of an adjacentset of baffle plates. Means are also provided for supporting the baffleplates for movement with the belts.

Various other features and advantages of the invention will be apparentfrom the following description of a preferred embodiment, from theclaims, and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of apparatus embodying the presentinvention and for forming a loosely felted mat of aligned wood flakes.

FIG. 2 is a plan view of a portion of the apparatus shown in FIG. 1.

FIG. 3 is a cross section view taken along line 3--3 in FIG. 1.

Before describing a preferred embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction nor to the arrangement of the componentsset forth in the following description or illustrated in the drawings.The invention is capable of other embodiments and of being practiced andcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

DESCRIPTION OF A PREFERRED EMBODIMENT

Illustrated in FIG. 1 is an apparatus for forming an elongatedcontinuous loosely felted mat 10 comprised of elongated wood flakes anda binder, this mat 10 being adapted to be placed in a press (not shown)and to be compressed therein to form a densified composite wood productsuch as is illustrated, for purposes of example, in the U.S. Lund et al.Pat. No. 4,241,133.

The apparatus illustrated in FIG. 1 includes a means for depositing afurnish comprised of a mixture of elongated wood flakes and a binderonto a supporting surface 12 to thereby form a loosely felted mat offlakes on the supporting surface. While the furnish may be comprised ofwood fibers, strands, particles or chips for use in makingparticleboard, fiberboard or flakeboard, in a preferred embodiment, thefurnish is comprised of a mixture of wood flakes and a binder materialas set forth in the U.S. Lund et al. patent referred to above. In suchan application it is preferred that the wood flakes be oriented in theloosely felted mat in mutually parallel relation and in parallelrelation to the longitudinal axis of the product to be formed, tothereby produce a compressed wood product having improved strengthcharacteristics. Additionally, it is preferred that the wood flakes ofthe furnish should have an average length of about 0.5 inch to about 3.5inches, preferably about 1 inch to about 2 inches, and an averagethickness of about 0.01 to about 0.05 inch. Flakes thinner than about0.01 inch tend to require excessive amounts of binder to be mixed withthese flakes if an adequate bonding of the flakes is to occur in thecompressed product. Flakes thicker than about 0.05 inch are relativelystiff and tend to require excessive compression in order to obtain thedesired intimate contact therebetween. In any given batch, some of theflakes can be shorter than 0.5 inch and some can be longer than 3.5inches so long as the overall length of the flakes is within the aboverange. The same is true for the thickness. To facilitate properalignment of the flakes, it is preferred that the flakes should have alength which is several times the width. Using this constraint as aguide, the average width of the flakes should be about 0.1 to 0.5inches.

The furnish is formed by introducing flakes of the size described aboveinto a conventional blender wherein predetermined amounts of a binderare applied to the flakes as they are tumbled or agitated in theblender. Suitable binders include those used in the manufacture ofparticleboard and similar pressed particle products. Such binders mayinclude organic polyisocyanates including those curable at roomtemperature or urea formaldehyde.

Referring again to the means for depositing the furnish onto thesupporting surface 12, while various depositing means could be employed,in the illustrated arrangement that apparatus includes a plurality ofhoppers 14 positioned in adjacent relation above the supporting surfaceand spaced along the length of the supporting surface 12. Each of thehoppers 14 supports a quantity of furnish and includes an opening 16 fordepositing the furnish on the supporting surface. In the illustratedconstruction each hopper includes a pair of picker rolls 18 positionedclosely adjacent to the opening 16 for controlling the quantity offurnish falling onto the supporting surface 12 in an evenly dispursedpattern. Since there are three hoppers 14 positioned in series along thesupporting surface, as the supporting surface moves continuously underthe hoppers, the mat thickness will build up to the desired level.

The supporting surface 12 is constructed so as to be adapted to becontinuously moving and to receive wood flakes deposited by the hoppers14 and for continuously carrying the loosely felted mat 10 to a secondconveyor 20 or to a press apparatus where the loosely felted mat 10 canbe compressed to form a densified composite wood product. While themeans for forming the supporting surface 12 can have variousconstructions, in the illustrated arrangement, the means for forming thesupporting surface includes a plurality of narrow conveyor belts 22positioned in closely adjacent relation, the conveyor belts 22 beingpositioned sufficiently close together so as to define a generallyuniform supporting surface 12 for receiving flakes from the hoppers.

Means are also provided for causing mutual alignment of the flakes asthey are deposited on the supporting surface 12 and for maintainingalignment of the flakes as they fall onto the supporting surface and onthe mat being built up on the supporting surface. In the illustratedconstruction, such means includes a plurality of thin planar baffleplates 24 positioned between the conveyor belts 22. More particularly,the aligning means are comprised of a plurality of sets of baffles orbaffle plates 24, each set being comprised of a plurality of baffleslying in generally coplanar relation and positioned in mutually abuttingrelation and lying in a gap between two of the conveyor belts 22 to forman elongated continuous baffle. The baffles 24 in each set are thusarranged so as to define a continuous loop including an upper flight anda lower flight. The illustrated construction also includes a pluralityof sets of baffles, with one set being positioned in each elongatednarrow gap between the respective conveyor belts 22 and such that thebaffles of respective sets are positioned in parallel closely adjacentrelation. As an example of a preferred spacing between the sets ofbaffles, when the furnish is comprised of flakes having the geometryreferred to above, a suitable spacing between baffles 24 may be 5/8inch, center-to-center of the baffles.

While the baffles 24 may be constructed of various materials and haveother shapes, in the particular arrangement illustrated the baffles 24are comprised of sheet metal. The thickness of the baffles as shown inFIGS. 2 and 3 is exaggerated for ease of illustration. The baffles 24are shown as each being generally rectangular including linear sides oredges 28 and a linear upper edge 30, but having a lower edge 32 which isrounded so as to have a semicircular shape. The baffles 24 of each setare adapted to be arranged with their lateral edges 28 in parallelabutting or closely adjacent edge-to-edge relation and with the upperedges 30 of adjacent baffles forming the upper and lower flights beingcolinear. In other arrangements the baffle plates could be circular andwith the edges of adjacent baffle plates overlapping.

Means are also provided for supporting the baffle plates 24 and forcausing movement of the baffle plates with the belts 22. In theillustrated arrangement, the means for supporting the baffles 24includes a plurality of baffle support shafts 34, the baffle supportshafts 34 being horizontal and extending perpendicularly to thedirection of movement of the supporting surface 12. The support shafts34 each extend through the centers of a plurality of baffles 24positioned in parallel spaced apart relation, and the baffles 24 areheld in spaced apart relation on the baffle shafts 34 by spacer rings 36surrounding the baffle shafts 34 and with one spacer ring 36 positionedbetween each pair of baffles 24. The opposite ends of the baffle shafts34 are connected to chains 38, and the chains 38 are each supported attheir opposite ends by drive wheels 40. While various means could beprovided for rotatably supporting the drive wheels 40, in theillustrated construction, the apparatus includes a frame 42 comprised ofa pair of spaced apart horizontal beams 44 parallel to the direction ofmovement of the supporting surface 12. The beams 44 are held in spacedrelation by transverse beams 46, and the frame 42 is supported by legs48. The beams 44 support bearings 50 which in turn rotatably supportopposite ends of drive shafts 52 supporting the drive wheels 40.

Means are further provided for supporting the upper horizontal flightsof the chains 38, this means including a pair of tracks 56 havingupwardly opening channels 58 for slideably supporting the chains 38. Thetracks 56 are welded to the upper portions of the main beams 44 of theframe 42 so as to be fixedly supported. The channels 58 of the tracks 56support the chains 38 and consequently the baffle shafts 34, such thatthose baffle shafts, supported by the upper flights of the chains 38,are held in substantially coplanar alignment and are not permitted tosag intermediate the drive wheels 40.

The baffles 24 are supported on the baffle shafts 34 such that the upperedges 30 of the baffles 24 supported by the upper flights of the chains38 are positioned closely adjacent the openings 16 of the hoppers 14 asthe baffles 24 move beneath the hoppers. By providing the baffles with arounded or semicircular lower edge 32 and by supporting the baffles 24on the baffle shafts 34 such that the axes of the shafts extend throughthe center or axes of the semicircular portion, the baffles 24 can movearound the axes of the drive shafts 34 without interference of adjacentbaffle plates. To facilitate such movement of the baffle plates, it isimportant that the baffles 24 are supported on the baffle shafts 34 withthe axis of the shafts 34 being intermediate the opposite edges 28 ofthe baffle plates and spaced from the bottom edges 32 of the baffleplates by a distance equal to one-half the width of the baffle plates,i.e. the radius of curvature of the rounded lower edge 32 of the baffleplates.

Means (not shown) are also provided for driving at least one of thedrive shafts 52 and for thereby driving the drive wheels 40 and thechains 38. While various means could be provided, in one arrangement anelectric motor could be drivingly connected by means of reduction gearsto the drive shaft 52.

It should be noted that in the illustrated construction, the narrowconveyor belts 22 have a width approximating that of the spacing betweenthe baffles 24, and the upper flights of the belts 22 are supported bythe baffle spacers 36, in turn supported by the baffle shafts 34. Theconveyor belts 22 are also supported by a roller 60 rotatably supportedby the ends of the frame beams 44.

While in the illustrated construction a plurality of conveyor belts 22are positioned between the baffles 24 and form the supporting surface12, in other arrangements other suitable flexible means could beemployed in place of the conveyor belts and to form a suitablesupporting grate. Accordingly, as used herein and in the claimshereinafter, the term conveyor belt should be read as including anyelongated flexible endless member suitable to support the mat.

In operation of the belts 22 and the baffles 24 described, as the chains38 cause continuous movement of the baffles 24 and the belts 22 underthe hoppers 14 the flakes deposited by the hoppers 14 will fall betweenthe baffles so as to become aligned in substantially parallel relationto the planes of the baffles. As the flakes fall between the baffles,they will assume a horizontal orientation and they will maintain theirmutually parallel alignment and be aligned with the direction ofmovement of the supporting surface 12. As the baffles 24 and the belts22 continue to move away from the hoppers 14, the baffles will then bepulled downwardly around the drive wheel 40 shown at left in FIG. 1through the wood flakes leaving the mat supported by the conveyor belts.

During the depositing of the wood flakes by the hoppers 14, the flakesare deposited in a random orientation and some of the flakes will notfall between the baffles 24 and will lie across the upper edges of thebaffles. Means are also provided for causing any flakes falling from thehoppers 14 across the baffles to be aligned with the baffles and to falltherebetween. In the illustrated construction, that means includes apair of picker rolls 64 positioned adjacent the hoppers 14 butpositioned in spaced relation from the hoppers in the direction ofmovement of the supporting surface 12. The picker rolls 64 each includea rotatably driven central shaft 66 extending perpendicularly to thedirection of movement of the baffles and adjacent their upper edges 30.A plurality of fingers or rods 68 are joined to the shafts 66 alongtheir lengths and extend radially outwardly from the shafts. The pickerrolls 64 are rotatably driven in the counterclockwise direction as seenin FIG. 1 and such that the radially extending fingers 68 will sweepdownwardly between the baffles 24 to engage any flakes lying across thebaffles. The fingers 68 will push these flakes into alignment with thebaffles 24 whereupon the flakes will fall between the baffles.

Means are further provided for pressing the loosely felted mat 10against the supporting surface 12 to precompress the mat material. Whilethe means for pressing the mat material may have various constructions,it includes a plurality of discs 70 supported for rotation by ahorizontal shaft 72. The discs 70 are supported so as to includeportions extending down between the baffles 24 to engage the mat. Thediscs 70 each have a width approximating that between the baffles 24 andare spaced apart by distances approximating the thickness of thebaffles. Means are also provided for biasing the discs 70 downwardlyagainst the surface of the mat 10, the biasing means being shown in theillustrated construction as comprising compression springs 74 supportingthe shaft 72.

Means are also provided for supporting the edges of the mat 10 as themat moves past the baffles 24 and is carried by the conveyor belt 22 tothe conveyor 20 or to a press. In the illustrated arrangement, thismeans includes a pair of conveyor belts 80 positioned on opposite sidesof the mat 10, the belts 80 each including an inner belt flight portion82 having a substantially vertical surface engageable against the edgeof the mat 10. The belts 80 are supported at their opposite ends byrollers 84.

Various features of the invention are set forth in the following claims.

We claim:
 1. Apparatus for forming a continuous elongated loosely feltedmat of thin elongated wood flakes with the flakes being aligned inmutually parallel interleaved relation, the apparatus comprising meansdefining a mat supporting surface and including a plurality of conveyorbelts positioned in adjacent side-by-side relation and means forsupporting the conveyor belts for continuous movement as a conveyor,means for depositing wood flakes onto the supporting surface to form aloosely felted mat, means positioned between the means for depositingand the supporting surface for aligning the wood flakes in substantiallymutually parallel relation and in substantially parallel relation to thedirection of movement of the supporting surface and for maintaining thewood flakes in substantially parallel alignment as the flakes fall fromthe means for depositing onto the supporting surface, said means foraligning and maintaining alignment including a plurality of sets of thinplanar baffle plates, each of said sets including a plurality of thinplanar baffle plates supported in generally coplanar alignment and inmutually adjacent relation to form an elongated continuous baffle andeach of said sets being positioned between pairs of said conveyingmembers, said baffle plates of one set being separated from said baffleplates of an adjacent set by one of said conveyor belts and parallel tothe baffle plates of an adjacent set of baffle plates, and means forsupporting said baffle plates for movement with said supporting surface.2. Apparatus as set forth in claim 1 wherein said baffle plates lie invertical planes and wherein at least a plurality of said baffle plateseach include a first portion adapted to extend upwardly from betweensaid conveyor belts.
 3. Apparatus as set forth in claim 2 wherein saidfirst portion includes an upper edge adjacent said means for depositingand vertical sides positioned in adjacent side-by-side relation withlinear sides of adjacent baffle plates.
 4. Apparatus as set forth inclaim 2 wherein each of said plurality of plates include a lower portionextending below said supporting surface, said lower portion having acurved edge forming a semicircle.
 5. Apparatus as set forth in claim 1wherein said means for aligning and maintaining alignment includes aplurality of baffle support shafts, conveyor means for supporting saidshafts for continuous movement, said shafts being supported inhorizontal relation and with their longitudinal axes in mutuallyparallel relation and being perpendicular to the direction of movementof said mat supporting surface, a first group of baffles supported inspaced stacked relation on a first one of said shafts, said baffles ofsaid first group defining planes perpendicular to the axis of said firstshaft, and a second group of baffles supported in spaced stackedrelation on a second shaft, said baffles of said second group definingplanes perpendicular to the axis of said first shaft, and said bafflesof said first group including edges closely adjacent edges of saidbaffles of said second group.
 6. Apparatus as set forth in claim 5wherein said conveyor means supports said shafts and said baffles forhorizontal movement beneath said means for depositing.
 7. Apparatus asset forth in claim 1 wherein said means for depositing wood flakes onsaid supporting surface includes a plurality of hoppers positioned inspaced relation along the length of a portion of said supportingsurface, said hoppers each including means for depositing flakes ontosaid supporting surface and said hoppers depositing flakes on saidsupporting surface successively as said supporting surface moves beneathsaid hoppers.
 8. Apparatus as set forth in claim 1 and further includingmeans for pressing said mat against said supporting surface, said meansfor pressing including a plurality of planar circular discs and meansfor supporting said discs above said supporting surface with said discsextending between said baffles and with said discs engageable againstsaid mat for forcing it against said supporting surface.
 9. Apparatus asset forth in claim 1 wherein said means for aligning said wood flakesincludes means for causing wood flakes from said hopper to fall betweensaid sets of baffles and including a rotatable shaft positioned abovesaid baffles, a plurality of fingers disposed along the length of saidshaft and extending radially outwardly from said shaft, said fingersbeing positioned so as to extend downwardly between said sets of baffleswhen said shaft rotates and to contact flakes lying across said sets ofbaffles, and means for causing rotation of said shaft.